Dye sensitized solar cell that surfaced in the early 1990s from the pioneering work of Micheal Gratzel and Brian O' Regon highlighted the use of cheaper, easily manufactured materials and a more sustainable approach to convert sunlight to electrical power. These cells from front to the back, are made up of a transparent conductive oxide coated glass (TCO), a porous metal oxide layer (the anode) to support light sensitive adsorbed dye molecules and also to aid in electron transport to the TCO, a liquid/solid-state electrolyte that facilitates electron transfer for dye regeneration by ion transport from redox reactions. The electrolyte is sandwiched between the anode and a TCO coated platinum cathode to catalyze the reduction and oxidation reactions of the redox species in the electrolyte (O'Regan and Gratzel; 1991). This cell technology has shown high prospects over amorphous silicon and hetero-junction solar cells which have production cost due to their very high purity requirements.
Since few years different materials of varying optical and electrical properties (WO2011041762A2, 2011); particles of varying morphology and architecture; dyes with different aggregation; speed of electron injection and HOMO-LUMO gaps; and electrolyte with different redox potentials and faster redox reactions, to enhance electron transport and reduce back current within the cell thereby increasing the efficiency of converting sunlight to electrical current are bring introduced.